Nintendo's Shigeru Miyamoto and his colleagues were dismayed when the original New Super Mario Bros. DS game was criticised for being too easy.
That's according to the latest instalment of Iwata Asks, for which Nintendo president Satoru Iwata is joined by Miyamoto's closest collaborators, EAD general manager Takashi Tezuka and SRD president Toshihiko Nakago.
"I imagine the three of you probably took it quite hard when some people said that the DS version was a little too easy. Miyamoto-san in particular," Iwata suggested during a discussion about difficulty in the Mario series.
"I think that was particularly true of Miyamoto-san," Nakago agreed. "So this time we've got a difficulty level the player can enjoy. I'd really like people to experience this for themselves. There are times when you'll think: 'This game's a pretty tough nut to crack!'"
Perhaps fearing they had overcompensated, the trio were careful to implement New Super Mario Bros. Wii's excellent Super Guide system and Hint Movies, which include some awesome recordings of Mario Club testers.
"Sometimes they're so good that you'll find yourself laughing out loud!" Tezuka explained. "It is really tricky to record these videos though. For that reason, some members of the team would request that we let them correct things manually. But I had to put my foot down. If it's not all done by a human player, you'll lose that essential realism."
Tezuka also encouraged players to replay levels in NSMB Wii. "I'm approaching 50 and I can get right to the end, so I think if you play through the levels enough times, you'll be able to discover a whole new side to Mario."
Plus, it turns out Iwata has a dream. "I'd like to add something, if I may," he said.
"A hugely appealing part of the Super Mario Bros. franchise titles are that they can be enjoyed by both the person playing as well as by the people watching. I think of that as a kind of tradition that has been upheld ever since the very first Super Mario Bros. title. Now with this game, anyone who is watching can simply pick up a Wii remote and join in.
"That's why I'd say that you should start off by watching the game. Then, if you think it looks interesting, go ahead and join in. Even if you've never played a Mario game before and you try the single-player mode, while it may be a little tricky at first, there are plenty of features included in the game that will help you to make progress.
"I think lots of people who never thought they would have anything to do with a Mario game will become absorbed in New Super Mario Bros. Wii and, because of this, both people who had never played Mario before and players who have long enjoyed it will now have a shared interest. In addition, skilled gamers will be able to play alongside players who are not so skilled. That's my dream."
Other highlights from this instalment include the revelation that Tezuka - head of software planning - hadn't even heard of Pac-Man when he joined Nintendo in 1984, recollections that Miyamoto only allowed the original NES Super Mario Bros. team three hours' celebration before they got back to work on Zelda.